Screw press



Dec. 8, 1931. R. T. LANG 1,835,789

SCREW PRESS Filed Jan. 30, 1928 2 Sheets-Sheet 1 ,2izven/tofl Rickard TLaw d ff Patented Dec. 8, 1931 UNITED STATES PATENT OFFICE RICHARD '1.LANG, O1 WEEHA'WKEN, NEW JERSEY, ASSIGNOB TO AMERICAN VOI'I'E CONTACTCOMPANY, INC NEW YORK, N. Y., A CORPORATION 01' NEW YORK SCREW PRESSApplication filed January 80, 1928. Serial No. 250,421.

This invention relates to screw presses, and more particularly to screwpresses of the type designed to remove liquid from diluted substances,whereby dewatering and washing of 5 the substances is accomplished. Theimproved press is especially adapted for the treatment of pulp in papermills. It has been found in actual practice that the pulp delivered bythe resent types of screw press'es is considerably ried in theneighborhood of the outer circumference of the screw threads than nearthe bottom thereof, the difference in consistency between the outer andinner portions of the mass when it leaves the machine, often being farin excess of fifteen per cent (15%). This condition is hi hlyobjectionable, as uniform dryness of the pulp throughout the entire massis essential for its further treatment viz., bleaching, nitrating, etc.Moreover the degree of dryness of the pulp, controls the capacity of thescrew press to a considerable extent and experiments have shown that ascrew press delivering the pulp with a consistency of fifty 1per cent(50%) at the outside and thirtyve per cent (35%) at the inside, i. e.with an avera e dryness of forty-two and a half per cent g12 %)has sevenand a half per cent (7 less capacity than a screw press which deliverspulp with a uniform dryness of fifty per cent (50%) throughout.

The mechanisms heretofore known, which aim to obtain dgreater uniformitythroughout the presse mass, for example, hollow screws with perforationsin the body of the screw; rotating perforated shells in continuation ofthe screw body proper, etc., are inefficient due to the fact that thehigh friction between the perforated surfaces and the pulp causes thepulp to rotate with the screw thereby preventing proper pressing of themass.

An object of the present invention is to provide an improved screw presswhich will discharge a pulp mass having a substantially uniform degreeof dryness throughout, and which will ave a greater delivery capacitythan the presses heretofore known.

A further object of my invention is to provide a press having thedescribed characteristics, which is of simple and economicalconstruction, high efliciency, and great durability.

Generally stated one of the important features of m invention is torovide a s ut section at t e discharge end ofthe screw, avingconcentricinner and outer stationary walls, the inner wall of which issubstantially in alignment with the body of the screw and is formed withperforations to permit the free escape of li uid from the pressed mass.The outer wall may be imperforate or perforated as desired. Whenerforated additional liquid may be expelled rom the outer layers of thepulp mass through the perforations. It will be obvious from theforegoing that the inner layers of the pulp during a considerabledistance of their travel through the press will be free to-drain andthat the pressed pulp in the compartment is held against rotation. Thepulp treated by this new type of press is characterized by itssubstantially stated uniform dryness and maximum density throughout. Atthe discharge end of the spout section a throttling or plugging devicemay be arranged which is adapted to automatically yield when unusualpressures are encountered to permit the escape of pulp, and which can beadjustably regulated to yield at any desired predetermined pressure. Byregulating the throttling device to yield at difierent pressures massesof pulp of dlfierent degrees of density may be obtained as desired. Thethrottle may be further provided with an adjustable setting device whichpermits the distance between the outlet spout and the face of thethrottle to be controlled as desired. The degree of opening to which thethrottle is set together with the amount of pressure yieldingly exertedupon the throttle controls the density of the pulp delivered by themachine.

In the accompanying drawings,

Figure 1 re resents a top plan view of the discharge on of a screw pressembodying my invention,

Fig. 2 a vertical longitudinal central section of the constructionillustrated in Fig. 1,

Fig. 3, a sectional view on an enlarged scale showing the drainingcompartment and certain associated parts,

Fig. 4, a vertical transverse section through the outlet end of the resstaken through the cap and jacket and ooking toward the plug,

Fig. 5 is a vertical longitudinal section showing a modified form ofconstruction, and

Fig. 6 is a similar view showing an additional modified form ofconstruction.

In the practice of my invention referring descriptively to the specificembodiment thereof which is herein exemplified in Figs. 1 to 4 of thedrawings, the press comprises a worm screw 1 rotatably mounted in theperforated shell 2 of the casing 3 of the ress, to which the outletspout 4 is attache Integral with the spout is a cap 5 with the outerbearing 6 for the extended shaft 7 of the screw. To a flange on thebearing a perforated jacket or pipe 8 is attached. This pipe has alignum vitae or babbitted bushin 9 fastened to its free end, by means ofwhich the pipe is carried on the extended shaft 7 of the screw. Thebushing 9 is provided with holes and grooves through which water underpressure is su plied as a lubricant for theshaft 7 and the f f'ont faceof the screw 1. The water for the lubrication is supplied through thepipe 10 which is connected to the fresh water conduit of the mill. Apipe 11 leads the used water out of the bushing near the outlet 12 ofthe perforated pipe. Throu h this outlet the water which is pressed outrom the pulp is also disehar ed. The pressure of the water sup lied sould be highenou h to prevent pu p from entering between t e adjoiningfaces of screw 1 and bushing 9. Instead of lubricating the bushing, ananti-friction bearing can be used as well. The adjustable plug 13 isguided on the perforated pipe 8 and can be moved towards or away fromthe discharge end of the outlet spout 4 by means of slip collar 17,levers '14 swinging around pin 15 which is carried by the boss 16 on thecap 5. The levers 14 engage slip collar 17 which in turn meshes with thering-shaped groove of the plug 13. The pressure is applied to the plugor closure 13 by means of levers 18, weight spindle 19 and wei hts 20.The setting device is represent by spindle 21,

, WhlCh passes through the threaded fulcrum 22 and reposes in a cavity23 in the ca turning handwheel .24, the s lowers, thereby changing t 5.By indle rises and e distance be tween plug 13 and discharge end ofoutlet spout 4. The bar or fulcrum 22 has its ends rotatably mounted inthe lovers 18.

In F i .-5 the bearing 6 carrying the extended s left 7 of screw 1, islocated within the outlet spout 4 and connected to the latter by meansof two or more arms of an oval section, so as not to obstruct the free)assage of the pulp between the arms. The raring 6 extends towards thescrew carrying a perforated jacket 8', a ring 9 of anti-friction metalfastened to the inner face of the hearing and being used as seal betweenthe rotating screw 1 and the hearing. If desired, the bearing body canbe shaped in such a manner that perforated plates can also be insertedaround the conical part of the body in order to increase the total innerperforated surface through which the liquor pressed out from the pulppasses. The liquor is discharged through the vertical connecting arm 12which is hollow, this arm joining the bearin to the spout 4.

nstead of using a. plugging device with circular cross-section as shownin Figs. 1, 2 and 3, the plugging device in Fig. 5 consists of: 2 flapsor valves forming a closure 13, laterally limited by the 2 vertical sidewalls of the outlet spout. To the pins 15 of the flaps, levers 14 and 18are connected, the pressure on the flaps being produced by weights 20located on the levers 18.

Fig. 6 shows a third modification of my invention with the bearing 6 ofthe extended shaft 7 of the screw 1 close to the body of this screw. Thebearing 6 is again connected to the outlet spout 4 by means of two ormore arms of oval section. The bearing extends away from the screw andcarries a perforated jacket 8a. A bushing 9 of lignum vitae or babbittedmetal supports shaft 7; 10 and 11 represent water connections to and outof the bushing 9 for the same purpose as in Figs. 1, 2 and 3. 12 is theoutlet of the jacket 8a for discharging the liquor expelled from thepulp. This outlet is in the form of a perforated arm which connects thebearing to the spout 4 and other arms which need not necessarily beperforated may connect the spout 4 and bearing 6 together at otherpoints. The head of the bearing is cone shaped; 13 is the circular plugor closure having a cylindrical portion mounted to slide on the cap 4and a conical open end. In the innermost position of the plug, theconical end of this closure comes into contact with the end of thebearin and completely shuts the outlet spout in this position. Thisshape of the plug allows an extremely fine regulation of the pressureand the passage area. of the pressed out pulp. The movement of the plugand its setting device corresponds exactly with those of Figs. 1 to 5,and needs no further explanation.

In Flgure 5 the spout 4 has an extension nasopae 4' which carries thepart 23a bearing the socket for the spindle 21. The two levers 14 areconnected by a link 14a and the weighted lever 18 may be integral withthe lower lever 14. Attached to the upper end 15 is an arm 18a to whichis pivotally secured a threaded bearing block for the screw 21. InFlgure 6 the part of the spout 4 which has the socket for the s indle 21is shown at 23.

While have shown one of the preferred embodiments of my invention it isto be understood that various changes in form, arrangement and proceduremay be resorted to without departing from the spirit and scope thereofas defined in the appended claims.

I claim:

1. A screw press comprising a casing having a rotary screw therein toexpel liquid from the contents of the press, said screw having a reducedaxial portion projecting from its body, a spout projecting from thedischarge end of the press and extending around said axial portion, abearing for the adjacent end of said axial portion carried by the spout,a perforated jacket surrounding said axial portion between the bearingand body of the screw, said jacket enclosing a space to receive liquidexpelled from the contents of the press by the screw, and a bearingassociated with the jacket engaging the body of the screw.

2. A press comprising a casing, a rotary screw therein, a spout for thedischarge end of said casing, a bearing supported by the spout, thescrew having an extension which is received in said bearing, aperforated jacket surrounding the extension between the screw and thebearing, and enclosing a space between it and the extension, the hearinghaving an outlet leading from the space between the jacket and theextension, and a closure mounted to slide on said jacket to controlthe-delivery of the contents of the press.

3. A screw press comprising a casing, a

rotary screw in the casing, a spout for the discharge end of the casing,a bearing within said spout, an extension on the shaft received by thebearing, a perforated jacket on the bearing enclosing a space to receiveliquid expelled from the contents of the press, the bearing having anoutlet leading from said space, said bearing also having a conical end,and a closure having a conical end to co-operate with the conical end ofthe bear ing to control delivery of the contents from said press.

4. In a screw press of the kind described, a casing having a outlet end,a stationary cylindrical jacket located in the outlet end and definingwith the casing a delivery outlet for material, a member on the casingsupporting the jacket and provided with a bearing, a rotary screw withinthe casing having a reduced axial portion received in said bearing,

said jacket surrounding the axial ortion and extendin from the bearingto t e screw, a bushing interposed between the jacket and screw, andmeans for controlling the discharge of material through the deliveryoutlet.

5. In a screw press of the kind described, consisting of a casin havinga rotary screw therein and rovide with a fixed support at its outer en aperforated cylindrical jacket fixed to the support and extending intothe casing in coaxial relation to the screw, and definin with the casingan annular delivery outlet For the ress contents, a bushing associatedwith t e jacket and engaging the screw, and means for controlling thedischarge of the press contents through said delivery outlet, comprisingan annular plug slidable on the jacket toward and away from the deliveryoutlet, and weighted levers operatively mounted on the sup ort andconnected with the plug for norma ly urging the plug towards thedelivery outlet.

6. In a screw press of the kind described, consisting of a casing havinga rotary screw therein and provided with a fixed support at its outerend, a perforated cylindrical jacket carried by the support in coaxialrelation to the screw and provided with a bushing engaging the screw,said jacket defining with the outlet end of the casing an annulardelivery outlet for the press contents, means for controlling thedischarge of the press contents through the delivery outlet, comprisingan annular plug slidable on the jacket toward and away from the deliveryoutlet, a slip collar on the plug, a weighted lever fulcrumed on thesupport and connected with the slip collar whereby normally to urge theplug toward the delivery outlet, and a setting device for adjusting theposition of the lever.

7. In a screw press of the kind described, a casing with an outlet end,a rotary screw in the casing having a reduced axial portion extendingwell beyond the outlet end, means supporting the outer end of the axialportion including a spout and a bearing in the spout for the axialportion, a perforated stationary jacket forming a liquid receiving spacebetween it and the axial portion, said jacket extending from the bearingto the screw, and means controlling the delivery of the press contentsthrough the outlet end, comprising an annular plug slidable on thejacket toward and away from the outlet end, and weighted leversassociated with the cap nogmally urging the plug toward the outlet en 8.In a screw press of the kind described, a

jacket carried by the bearing an enclosinga space to receive liquid, andmeans controlling the delivery of the press contents through the outletend around the jacket, comprising an annular plug slidable on the 5jacket toward and away from the outlet end, and'weighted levers arran don the spout and connected with the ug for normally urging the plugtowards t e outlet end.

In testimony that I claim the foregoing as 10 my invention, I have si edmy name hereto.

RIC T. LANG.

